Resettable safety switch gauge



Feb. 7, 1967 F. W. MURPHY, JR., ETAL.

RESETTABLE SAFETY SWITCH GAUGE Filed Oct. l2,` 1965 ATTORNEYS United States Patent O Inc.

Filed (ict. 12, 1965, Ser. No. 495,126 7 Claims. (Cl. 20G-56) This invention relates to a safety switch for engines, and more particularly to a switch incorporated into a pressure gauge.

Internal combustion engines, particularly of the stationary type, are frequently left unattended for periods of greater or lesser duration. In the evenof lubricating system failure, serious damage results to the engine before it is stopped. Since these engines usually include an ignition system operated lfrom a magneto, the engine may be equipped with a safety switch as embodied in United States Patent No. 2,358,729 such that the engine will be stopped when-the oil pressure reaches a predetermined low.

Switches of this type cut off the engine by grounding the ignition system, such that when it is necessary to restart the device, some means must be provided to break the grounded ignition circuit in order to permit restarting.

In order to satisfy this operational requirement, the device embodied in United States Patent No. 2,722,576 was developed. The device disclosed in this patent includes a grounding switch constituting a fixed contact mounted on the periphery of the gauge extending through the side thereof, an electrical contact mounted on the gauge pointer for engagement with the stationary contact and a spring-biased operating means extending through the side of the gauge for selectively separating the movable contact from the stationary contact. Although this device has worked in a suitable fashion, there are certain disadvantages which have been found present in this device.

The safety switch of the aforementioned patent is usually mounted on a control panel which includes other gauges indicative of engine operating conditions. Because of the side mounting of the operating button and fixed Contact, it has been necessary to custom-lit the safety switch of this patent to a control panel to allow for the manipulation of the operating button and the connection of electrical wires to a fixed contact. Accordingly, installation of the switch gauge of this patent has been unnecessarily expensive often requiring a cutting of the control panel as by a hacksaw or torch before installation or by mounting the gauge away from the panel.

It is an object of the instant invention to provide a switch gauge which may be connected to an ignition circuit for grounding the circuit under predetermined conditions and which allows severance of the grounded circuit in order to permit restarting of an associated engine.

Another object of the instant invention is to provide a means for breaking a grounded ignition circuit, which after restarting of the engine will be automatically rendered ineffective so that the safety switch may operate in a normal manner.

Still another object of the instant invention is to provide a safety switch of the type described which may conveniently and readily be assembled in a control panel adjacent an associated engine.

A further object of the instant invention is to provide a switch gauge of the character described having an operating button for selectively positioning an electrical contact within the device for breaking an electrical circuit therein, the operating button extending through the customary transparent cover of the gauge.

A still further object of the instant invention is to pro- 3,33,302 Patented Feb. '7, 1967 ICC vide a switch gauge of the character described which may be mountedv flush with an instrument panel.

Other objects and advantages of the instant invention, as well as the invention itself, reside in the combinations of elements, arrangements of parts, and features of construction, all as will be more fully pointed out hereinafter and disclosed in the accompanying drawing wherein there is shown a preferred embodiment of this inventive concept.

In the drawing: v

FIGURE 1 is a front elevational View of the switch gauge of the instant invention;

FIGURE 2 is a vertial cross-sectional view of the device of FIGURE 1, taken substantially along line 2-2 thereof viewing in the direction of the arrows; and

FIGURE 3 is a horizontal cross-sectional view of the device of FIGURES 1 and 2 inclusive, taken substantially along line 3-3 of FIGURE l viewing in the direction of the arrows.

Referring now to the drawing in detail, wherein like reference characters designate like elements throughout the several views thereof, there is indicated generally at 10 a switch gauge of the instant invention comprising a housing designated generally at 12, a fluid measuring means shown generally at 14 including a pointer 16 and an operating means designated generally at 18 for selectively positioning pointer 16. As will be explained more fully hereinafter, pointer 16 indicates the pressure within the lubricating system or other iluid system of an associated device and when the pressure thereof falls to a predetermined low, pointer 16 contacts a stationary electrical contact closing an electrical circuit through switch gauge 10 thus grounding the ignition circuit of the associated engine. When it is desired to restart the lassociated engine, it is necessary to manipulate operating means '18 thus separating po-inter 16 from the fixed electrical contact breaking the grounded ignition circuit.

Housing 12 includes a transparent front .cover o1' face plate 20 made of a dielectric material, suc-h as glass, plastic, or the like, which is illustrated as circular in front elevation, but which may 4be of any suitable shape, having an annular rearwardly extending lilange 22 carrying a peripheral ridge 24. Housing 12 includes an annular metallic body 26 carrying an outwardly extending flange 28 juxtaposed to peripheral bulge 24 receiving annular flange 22 of front cover 20. Closing the rear of casing 12 is a metallic plate 39 connected by a circular shoulder 32 forming a diaphragm compartment 34 to an exteriorly threaded conduit 36 forming a passageway 38 therein communicating wit-h compartment 34.

Pressure measuring means 14 may be of any suitable type, but is illustrated as including a diaphragm 40 mounted within compartment 34 between a peripheral boss 42 and an apertured plate 44. Plate 44 is in t-urn secured in place by a coaxially apertured plate 46 secured about the interior of annular body 26. Diaphragm 40 carries a probe 48 extending through the apertures of plates 44, 46 contacting a bell crank shown generally at 50 in FIGURE 3.

Positioned interiorly of housing 12 is a plate 52 carrying a scale 54 adjacent the end of pointer 16 with indicia 56 designating the pressure within compartment 34 in a conventional manner. Plate 52 forms an opening 58 at the nadir thereof through which extends a pin 60 xedly secured to plate 46. The lower end of pointer 16 forms an aperture xedly receiving pin 60 for rotary movement of pointer 16. Pin 60 rotatably receives a U-shaped bracket 62 forming an aperture loosely receiving a spring wire 64 mounted on a stationary post 66 secured to plate 46 as may be seen in FIGURE 2. Bracket 62 carries an upstanding arm 68 for engagement with a stationary post mounted on plate 46.

As will be apparent to those skilled in the art, the build-up of pressure within compartment 34 will reciprocate diaphragm 40 thus causing -probe 48 to contact bell crank 50. One leg 72 of bell crank 50 will contact spring wire 64 to rotate bracket 62 and pointer 16 a distance proportional to` the build-up of pressure within compartment 34. Accordingly, an individual may observe scale 54 through transparent cover 20` and determine the pressure of the uid system being measured.

Operating means 18 includes a depressible button means shown generally at 74 mounted in front cover 20 by a body 76 which has an outwardly extending threaded section 78 receiving a threaded nut 80y securing button means 74 to cover 2U. rA depressible button 82 is reciprocably mounted within body 76 and is spring-biased to the outwardly extended position shown in FIGURE 3. Body 76 forms a pair of spaced apart arms 84 pivotally receiving a piv-ot pin 86 on which is mounted lan arm 88.

As may be seen in FIGURE 3, plate 52 provides a cutout 90 receiving arm y8S therethrough for purposes more fully explained hereinafter. An individuals pressing upon the outer end of button 82 results in the reciprocable movement thereof toward arm 88 with the inner end of button 82 contacting arm 88 and pivoting it about the axis of pin 86. Arm 88 is biased by a spring (not shown) surrounding pin 86 such that the inner end of button 82 and arm '88 are in contact at all times. It will be seen therefore, that the depressing of button 86 will pivotally move arm 88 .through cutout 90 in plate 52 with arm 88 returningto the position shown in FIGURE 3 when button 82 is released.

A lever shown generally at 92 is pivotally mounted on the rim of plate 52 by a -pin 94 and includes a first leg 96 positioned in the path of arm 88 for contact therewith upon the depressing of button S2. Lever 92 provides a sec-ond substantially L-shaped leg 98 extending through an opening 100` in plate 52. As may be seen in FIGURE 1, pointer 16 forms a ledge for receiving the end of leg 98 as will be explained more fully hereinafter. A spring 102 surrounding pivot pin 94 has one leg resting against a stationary post 104 affixed to plate 52 for biasing lever 92 ina clockwise direction when viewing gauge 10 in front elevation -as Iin FIGURE 1.

When it is desired to position pointer 16 in the location shown in FIGURE 1, such as to open a grounded ignition circuit as previously mentioned, it is necessary for an attendant to depress button `82 which will rotate arm V8s through cutout 96 with arm 88 contacting first leg 96 of lever 92. Lever 92 will rotate against .the biasing force of the spring surrounding pin 94 such that the end of second leg g'contacts pointer 16. Pointer 16 will be rotated about pin 60 until the end of second leg 98 resides in the ledge formed in pointer 16 as maybe seen in FIG. l.

Since button 82 has a limited distance of reciprocable travel, Iarm 88 will have limited pivotal m-ovement as will lever 92. Accordingly, second arm 98 will be positioned to reside in the ledge of pointer 16, which will be biasedy toward the zero indicia by spring wire 64. Because of the spring biased nature of operating button 812 and pivoted arm 88, the release of button '82 will be followed by a return of these components to the position shown in FIG- URE 3.

Referring now to FIGURE 1, body 76 of depressible button means 74 is connected by a thin metal strip 105 to a substantially triangular metallic plate 106 within the enclosure formed by front cover 20A and casing 12. Fastening triangular plate 106 to front cover 20` and providelectrical communication thereacross is a metallic stud In the use of switch gauge 10, metallic stud 108 may be electrically connected to a STOP switch of any suitable type for grounding the ignition circuit of an associated engine. As previously mentioned, housing 12 is made of metal or an electrically conductive material which is grounded in Va suitable manner. Whn 'the PTC-S- sure within compartment 34 subsides to a low-level, pointer 16 will move in a counterclockwise direction, as may be seen in FIGURE 1, until the upper end thereof contacts either arm 8S or arms 84 of depressible button means 74. Since depressible means 74 is also preferably of metal, an electrical circuit will be completed including housing 12, pin 60, pointer 16, depressible button-means 74, metal strip 105, triangular metal plate 106 and metal stud 108.

It will be seen, therefore, that the ignition circuit of the associated engine will be grounded, thus stopping it. In order to restart the engine, operating button 82 of depressible button means 74 will be pushed thus pivotally moving arm $8 into contact with first leg 26 of lever 92. The rotation yof lever 92 will result in second leg 9S thereof contacting and rotating pointer 16 in a clockwise direction shown in FIGURE l. It should be noted that arm 8S is bent away from rst leg 96 such that the release of button 82 substantially separates arm S8 and leg 96 to avoid electrical contact therebetween. When pointer 16 is held in the position shown in FIGURE 1, no electrical circuit exists across switch gauge 1t) because .pointer 16 is disposed away from depressible button means 74 with arm 88 being displaced from leg 96. It will be seen that depressible button means 74 acts as a fixed electrical contact with pointer 16 acting as a movable contact, although it should be understood that an additional contact may be provided in lieu of button means 74 while pointer 16 may carry a separate contact.

In order to provide a high pressure shut-down, a second electrical `contact shown generally at 116 is provided Within casing 12. Contact 116B is connected to triangular metallic plate 108 by a metallic stud 112 with an arm 114 connecting stud 112 to a stationary post 116 positioned in the path of movement of pointer 16 `adjacent the high pressure end thereof. lf the pressure being measured becomes too high, pointer 16 will contact stationary post 116 thus shorting out or grounding the ignition circuit of the associated mot-or.

Although the switch gauge of the instant invention has been generally described with reference to the lubricating system or an engine, it should be understood that it is not so limited. For example, pressure within irrigation lines may be measured with the device of the instant invention with Vthe igniti-on circuit of the compresn sor motor being connected through gauge 10 such that the loss of pressure within either the inlet or outlet flow lines may automatically stop the motor.

It should also be apparent that the restarting of an engine associated with the instant invention will automatically reset operating means 13 since pointer 16 will respond to increased pressure within compartment 34 to rotate pointer 16 in a clockwise direction shown in FIG- URE 1. When the terminal end of second leg 98 becomes disengaged with the ledge or shoulder of pointer 16, the spring surrounding pivot pin 94 will bias lever 92 in the clockwise direction shown by the arrow in FIGURE 1. n It is now seen that there is herein provided an improved switch gauge having all of the objects of the instant invention and others, including many advantages of great practical utility and commercial importance.

Since many embodiments may be made of the instant inventive concept, and since many modifications may be made of the embodiment hereinbefore shown and described, it is to be understood that the foregoing is to be interpreted merely as illustrative and not in a limiting sense.

We claim:

1. A gauge comprising a housing having a transparent cover, means cooperating with said cover forming an enclosure and conduit and condition sensing means com` municating through said housing into said enclosure, condition responsive means within said enclosure in communication with said condition sensing means for measa uring fluid -conditions including a pointer movably mounted through a predetermined range adjacent said cover, said pointer carrying contact means constituting one side of a grounding switch, a fixed contact carried by said housing engageable with said contact means when said pointer indicates a low predetermined reading, said xed contact constituting another side of said grounding switch, and operating means interior of said housing including a reciprocably movable push button extending through said cover, a pivotally mounted arm within said enclosure for engagement with said button and a lever pivotally mounted within said enclosure having a first leg positioned in the path of said pivotally mounted arm and a second leg positioned to engage said pointer for selectively positioning said pointer away from said low predetermined reading separating said xed contact and said contact means.

2. The structure of claim 1 wherein said Xed contact is electrically separated from said housing and said pointer.

3. The structure of claim 2 wherein said housing includes 'an outer periphery, said ixed contact and said movable means reside within said periphery providing for Hush mounting of said gauge.

4. The structure of claim 3 including electrically conductive means affixed to said transparent cover connected with said fixed Contact providing means for attachment to an electric wire.

5. The structure of claim 4 including -a high reading cutoff switch having a post mounted in the path of said pointer at a high predetermined reading, said post being connected to said electrically conductive means.

6. The structure of claim 1 wherein said second leg and said pointer include means for temporarily securing said pointer and said second leg together precluding movement of said pointer in a direction toward said low predetermined readingl and allowing separating movement of said pointer in a second direction.

7. The structure of claim 6 wherein said movable means includes spring means biasing said pivotally mounted arm out of contact with said first leg of said lever when said second leg and said pointer are temporarily secured together.

References Cited by the Examiner UNITED STATES PATENTS 9/1945 Murphy 200-56 11/1955 Murphy et al. 200-56 

1. A GAUGE COMPRISING A HOUSING HAVING A TRASNPARENT COVER, MEANS COOPERATING WITH SAID COVER FORMING AN ENCLOSURE AND CONDUIT AND CONDITION SENSING MEANS COMMUNICATING THROUGH SAID HOUSING INTO SAID ENCLOSURE, CONDITION RESPONSIVE MEANS WITHIN SAID ENCLOSURE IN COMMUNICATION WITH SAID CONDITION SENSING MEANS FOR MEASURING FLUID CONDITIONS INCLUDING A POINTER MOVABLY MOUNTED THROUGH A PREDETERMINE RANGE ADJACENT SAID COVER, SAID POINTER CARRYING CONTACT MEANS CONSTITUTING ONE SIDE OF A GROUNDING SWITCH, A FIXED CONTACT CARRIED BY SAID HOUSING ENGAGEABLE WITH SAID CONTACT MEANS WHEN SAID POINTER INDICATES A LOW PREDETERMINED READING, SAID FIXED CONTACT CONSTITUTING ANOTHER SIDE OF SAID GROUNDING SWITCH, AND OPERATING MEANS INTERIOR OF SAID HOUSING INCLUDING A RECIPROCABLY MOVABLE PUSH BUTTOM EXTENDING THROUGH SAID COVER, A PIVOTALLY MOUNTED ARM WITHIN SAID ENCLOSURE FOR ENGAGEMENT WITH SAID BUTTON AND A LEVER PIVOTALLY MOUNTED WITHIN SAID ENCLOSURE HAVING A FIRST LEG POSITIONED IN THE PATH OF SAID PIVOTALLY MOUNTED ARM AND A SECOND LEG POSITIONED TO ENGAGE SAID POINTER FOR SELECTIVELY POSITIONING SAID POINTER AWAY FROM SAID LOW PREDETERMINED READING SEPARATING SAID FIXED CONTACT AND SAID CONTACT MEANS. 